Airplane catapult



Aug. 23, 1938 H. c. RICHARDSON ET AL 2,127,531 I AIRPLANE CATAPU'LT Filed Nov. 26, 1927 ma U, a w w um Mk 5; mm w Mm: F & CM NM W MM L our HWB .1 T L W m m -H W.

H, c. .RAICHARDSON ET AL 2,127,531

' Aug. 23,1938.

AIRPLANE CATAPULT 9 Sheets-Sheet 2 Fii ed Nov. 26, 1927 /NVEN TO R5 #040 EN C. P/crmposozv,

IIIIIL: l l Illl .llllll U M? P M M m M w @Q Aug. 23, 1938. H. c. RICHARDSON ET AL AIRPLANE CA' IAPULT i HT A'ug. 23, 1938.

H: c; RICHARDSON ET AL 2,127,531

AIRPLANE CATAPULT I Filed Nov. 26, 1927 9 Sheets- Sheet 4 [mun-ans (1'01. 01: C. Plan/mason. WILLIAM M. FELLEIPS 6 W law flfi'onuey I H. c. RICHARDSON ET AL 7,531

Aug. 23, 1938.

AIRPLANE CA'IAPULT m a 9% N* 6 m r .mwlmr l .wM HUM a hm I--- m -+m W km NW n 9 NM NM Q Filed NOV. 26, 1927 N am F H. mM PM Gm Nu El mW H 23, 1938. v H. RICHARDSON ET AL 2, 7, 31 I AIRPLANE GATAPULT Filed Nov. 26, 1927 9 s eets-sheet 7 m-wdi //VVEA/TOES N Ms D 0M NM M. Z

j Arr oR/vEY Aug. 23, 1938. H. c. RICHARDSON ET AL AIRPLANE CATAPULT Filed Nov. 26, 1927 9 Sheets-Sheet s INVENTORS Howl/v CCP/ch'A/wsau 9 Wa /4N1 M. Fsuses Augf23, 1938. H. c. RICHARDSbN ET AL 2,127,531

AIRPLANE mum Filed Nov. 26, 1927 9 Sheets-Sheet 9 6 7 as .a l a .7 M m INVIENTORS Hows/v C. RICHARDSON, W/LLIAMMFELLERS Patented Aug. 23, 1938 UNITED STATES PATENT OFFICE AIRPLANE CATAPULT Holden 0. Richardson and William M. Fellers,

Washington, D. C.

Application November 26, 1927, Serial No. 235,910

33 Claims.

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 O. G. 75'l) l stances to fasten the aircraft to the launching car and to releasethe same ata given point in the travel of said car and to provide said car with Wheels, but the high velocity of said car-attained in, such relatively short distance, tends to produce 15 flattened surfaces on said wheels.

We have devised the novel method of, and, to demonstrate its utility, such means whereby, dispensing with wheels for said car and providing a relatively small bearing surface at each corner 20 of said car and on opposite horizontal sides of.- each car rail, and lubricating said rails, more eflicient bearing as well as guide for said car-is attained; and'that by securing the aircraft to said car at a plurality of points separated from each 25 other in their direction of travel and so as to prevent substantial relative vertical movement therebetween while said securement holds, little if any lubricant is required for said rails and the action of said aircraft upon the air during the 30 launching movement progressively lessens'the load upon the car and then of said car upon its rails then tending to facilitate acceleration and upon the release of said securement, the resulting friction of said car bearingson said rails is 35 restored and in the 'unlubricated condition of said rails, tends to contribute to the deceleration of said car; and further by progressively releasing said securements from the rear forward, the foremost being released substantially 40 at the time of commencement of the deceleration of said car, that the aircraft is not only. securely retained on said car during the major partofits launching movements against lateral winds and other displacing tendencies, but that said pro- 45 gressive releasing accomplishes said tendencies to facilitate acceleration and deceleration.

We have further devised the novel method of,

and, to demonstrate its utility, such means whereby, applying pressure in one direction,

0 launches the aircraft, and applying some of said pressure at substantially in right angle to said direction decelerates the launching means.

We have further devised the novel method of, and to demonstrate its utility, such means 55.Wl1ereby, the launching means is secured in its initial position, pressure is applied in one direction to launch the aircraft and applying some of said pressure at a different point to release said securement after some of said first named pressure has been applied; as well as further, 5 said first named pressure is accelerated substantially from the time of said release to substantially the time when the aircraft commences to leave the launching means.

The primary object of our invention is to provide a method'of and means whereby the expansive force of compressed air may be used in launching airplanes.

' Another object of our invention is to provide a method of and means to, regulate the admission of the compressed air during the operation of the catapult so that an even acceleration in speed of launching is produced and in this manner reduce the irregularity of motion, shock and jars to'a minimum.

Another object of our invention is to provide a catapult operating mechanism that is simple in construction, compact, easy to operate, one requiring a minimum of working parts, and one which safely reduces to a minimum the number of personnel required in attendance during its operation. We have accomplished this object by the utilization of a single manually operated valve, and other means conveniently located that controls the various detail movements of the catapult and the plane thereon;

Other objects of our invention are to provide a reliable and emcient means for securing under v stress the airplane to the launching mechanism during the preliminary period of engine testing and warming up and during the accelerated travel, a means for releasing the stress upon the means for securing the aircraft to the launching means and automatically releasing said securing devices progressively near the termination of the run when the proper speed for launching the aircraft has been'attained to enable the airplane to proceed under its own power, and also means for operating an efficient braking mechanism to bring the launching mechanism to a gradual stop at the end of the launching run. Our method may be practiced advantageously by any of many different forms of apparatus as may be readily understood by those skilled in this art after becoming familiar with our method and the various steps thereof, andthe apparatus'we' have devised for the most advantageous practice of the same.

Our invention consists substantially in said method, and in a means aspect, the construcsociated therewith or as will be more fully here inafter set forth as shown by the accompanying drawings and finally pointed out in the appended claims.

Reference is to be had to the accompanying drawings forming a part of this specification in which like reference characters indicate corresponding parts throughout the several views, and in which:

Figure 1 is a front elevation of a catapult showing an airplane in launching position,

Figures 1A, 1B and 1Cv represent a top plan view, partly diagrammatic, of a catapult embodying this invention,

Figures 2A, 2B and 20 represent aside elevation of the same, also partly diagrammatic,

Figure 3 is a view partly in plan and partly in horizontal section of a portion of the valve control and its associated mechanisms,

Figure 4 is a vertical transverse section on the line 4-4 of Figure 3,

Figure 5 is a detail plan view of a storage tank system for the accumulation of compressed air,

Figure 6 is a plan view, partly in section 0 the main power or driving unit,

Figurefl is a view in side elevation of the parts shown in Figure 6,

Y Figure 81s a vertical transverse section through the cross head, speed multiplying sheaves, and

valve control cam shown in Figures 6 and 7,

Figure 9 is an enlarged detail view of the valve control cam and associated parts, shown and described with reference to Figure '1,

Figure 10 is a view in front elevation of the master control valve,

Figure 11 is a horizontal section on the line of Figure 10, with the head removed to expose the air ports of the valve seat,

Figure 12 is a detail horizontal section through the valve head showing the location of the ports,

Figures13 to 20 inclusive are detail sectional views of the master control valve shown in Fig.- ures 10 and 11 to illustrate the order in which the ports are brought into operation,

Figure 21 is a vertical section through the rear portion of the catapult beam, and launching car, showing the locking and releasing mechanism for holding the car in readiness for launchin Figure 22 is a vertical section through the launching car and the catapult track,- showing the relative position of the brake mechanisms on the car and track when the car approaches the end of the launching run,

Figure 23 is a detail vertical transverse section on the lines 23-23 of Figure 21, 1

Figure 24 is. a vertical transverse section through the central bearing of the catapult, showing the air tight, revolving joint through which the air is S lDplied to the relay tank, and

Figure 25 is a detail plan view of a split collar of the joint shownin Figure 24.

Referring particularly to Figures 1 and 22, numeral designates the beam or table of a catapult consisting ofstructural members la running lengthwise of the beam, and side, top and bottom plating lb, which are reinforced at intervals by angles Ic. Rails 18, are provided at the side of the beam I. for guiding a car 8 upon which an airplane 6 is mounted. The beam i is mounted to rotate upon a stationary turntable base 2. The rotation of the beam is controlled by a ring gear 3, a pinion 3a, worm gearing 4 and a hand wheel 5, Figures 1, 13. I v

The airplane 6 is provided with a centrally located float i, which is securely held to the launching car 8 by cables 9 and i0. It is to be understood that any modification of the launch ing car to adapt its use with any style of landing gear of the wheel or float type is within the scope of this invention.

Referring to Figures 1, 1A, 2A, 21 and 22 the car 8, consists of a body portion ll, upon which is mounted the supporting elements for the airplane 6. In the case of the particular type of float I shown we have found that the elements necessary for the positive acceleration and release of the airplane, are a rear saddle support l2, a step block l3, and a keel member |3a The airplane is secured to the car 8 by means of the cables 9 and 10, which are attached at their upper ends to the float 1 or other portions of the aircraft at points slightly forward of the rear and front respectively of the launching car 8. The cables 9 extend downwardly and forwardly and normally under stress engage the hooks or horizontal pins l9 located on opposite sides of a portion of the air-craft and at the forward end of the launching car. The cables I0 extend downwardly and rearwardly and the hooks in the lower ends of said cables I0 normally under stress engage their respective pins 21 at a pointbetween the keeper plates 20. The pins 2| are each separately connected to their respective brackets 23 by a slack cable 22 of the proper length to insure the requisite delayed release of the hooked lower ends of each of the cables in. v

When, for instance, no cross wind is blowing, the cables 22 may be of uniform length and thus they will pull their pins 2| simultaneously; but with a cross wind blowing, or other lateral disturbing agency is present, the cable 22 on the side from which said Wind or agency comes, is

its release.

The function of the rear cables I0 is a three fold one; first, they prevent the airplane moving forward relative to the launching car during preparatory period when the engine may be running and exerting a tendency of translation by action of the propeller; secondly, they prevent the airplane rotating forward on its nose due to engine and propeller action, and thirdly, they prevent the airplane from capsizing sideways due -to side wind, lateral ,rolling'of the support of the catapult or, other kindred cause.

Immediately after launchingcommences, and before the slack has been taken out of-{the cables 22, the acceleration force thereby exerted tends to seat the airplane 6 firmly against the step block |3 and rear saddlesupport l2 of the launching car. This tendency releases the stress of each cable l0 upon its pin 2| and thus makes it possible for the cables 22 to pull the pins 2| out of their keeper plates 20, simultaneously or alternately as may be controlled by'the prede moved by said acceleration seating said plane the stress on which has been relieved, relieving to pull the pins against block l3 and support i2 at the deferred time for their removal, it takes very little force 2i out of the keeper plates 28 at a predetermined time and release'the said relaxed cables I0. I r

This affords a safe, certain and efiicient methd of releasing the rear end of the airplane from car 8.

The forward cables 9, remain engaged with the hooks or horizontal pins I9 at the forward end of the car 8, and prevent the airplane from lifting away from the car 8 until near the forward terminal of the travel of the launching car 1 8 is reached, when the car 8 will commence to decelerate its velocity due to engagement with the braking system and the fact that the expansive force thrusting said car 8 has passed its maximum and is subsiding while the propeller is approaching the attainment of flying speed.

At this point the lower looped ends of the cables 9 will free themselves from the hooks or horizontal pins' [9 as the airplane leaves the car, as

shown in Figure 20, the said angularity of cables 9 and the relative forward motion of the aircraft and launching car 8 releases the stress of the hooked lower ends of the cables 9 upon, and frees from, their respective hooks or horizontal pins I9, at the time of the launching of the air-' craft.

It will be apparent from the the next precedingly described novel means has been devised by us to exemplify the practical and novel utility of our improved method for securing and releasing aircraft to and from their launching cars,which forms a unitary and related part of our invention and that said method broadly contemplates the fore and aft securement under .stress of an aircraft to its launching and releasing means, relieving the stress on one of said securements, then releasing saidsecurement the stress on the other of said securements, and releasing said other securements; while in its different aspects of lesser breadth said method may be qualified such that said first named stress relieving and securement-release is occasioned early in the launchingmovement, while the latter relieving and securement release are designed said craft is to be launched;v starting the launching; then relieving said stress upon the rearward of said securements; then releasing said rearward securement; then relieving said stress upon the forward of said securements; then releasing the forward securement preferably at the ,time when said craft attains a velocity substantially in excess of that of its launching means or car 8.

While in its aspects of lesser breadth the same. may be qualified in the first'of said relieving and releasing steps is occasioned as to its relieving by the initial relative movement of said craft and its launching means or car 8 and its release is occasioned at a definite point in the launching movement at which said point the relative velgcity of said craft and the air is such that, with the forward securements still under stress, the pilot may, by the craft controls, retard any tendency of said craft toward departing from its normal navigating position on said launching foregoing that means or car 8, and said relieving of said stress upon the forward securement is occasioned by the initial forward movement of said craft relative to its launching means or car 8, and releasing of said forward securement is occasioned by the continuance of said relative movement.

The brackets 28, are hinged at 23a, Figures 2A and 21, to a hinge plate 23b, secured to the rear end of the supports upon which car 8- travels and at a point below the top surface of said supports, so that said brackets 23 may be swung backward about their pivot points 23a and thus lowered to permit the removal or replacement of the car from the rear of the catapult, and said brackets 23 in' their respective vertical position, are prevented from forward movement by contact with the rear ends of the supportsto which their hinge plates 23b are secured.

The car 8 is guided along the track iii of the catapult beam l, by shoes I'I that are preferably located at the four corners of the body portion ll of car 8 and hook over the outer web of angle iron track iii. A centrally located brake member I4 is secured to the under side of the car 8, the function of which will be hereinafter described in connection with the braking element.

Securedto the brake friction member 14, at a point 24, Figures 1A and 2A, toward the forward end of the car 8, is a force transmitting cable 25, which transmits the propelling force of the compressed air by means of a force multiplying mechanism to accelerate the car 8 and the airplane removably secured thereon.

In its launching movement car 8 travels preferably at the uniform rate of three times the acceleration of gravity while in its braking move- 'ment it is slowed up preferably at a uniform rate as high as one hundred times the acceleration of gravity. Such velocities, and their stresses which are essential to practical launching, require that car 8,- and members of the launching mechanism movable therewith, be made as light as possible and that wheels be dispensed with on said car 8 and that bearing feet ll, slotted to receive loosely the rail l8, be provided in lieu of rollers as bearings for car 8 on rail i8, said slotted bearings l1 tions. The travel of the plane, and its fore and aft securement to car 8, in its launching movement, relieves the weight of said car and its load from the track, and when the plane is released from said car its friction on said track is reguide car 8, on rails I8, in all direcstored thereby and tends slightly to effect deceleration.

While this tendency is relatively small, yet with the high velocity essential in such extremely limited space as a ship, for instance, affords therefor, great refinements of detail, and perfect coordination in all respects, are prerequisite to successful and safe practical results, and without each of which failure is inevitable with its attendant losses of life, property and otherwise.

The cable 25 extends forward over a sheave 88, Figures 10, 20, that is located at the forward end of the catapult beam I; thence back ,over guide sheaves 38a and thencealternately around a plurality of the separate grooved pulleys of separate sheaves 32 and 85 and is secured at 3] to crosshead 8|, Figures 1B, 2B, 6 and '7. These sheaves are carried by a movable crosshead 3.l and a stationary crosshead 34.

Referring to Figures 21 and 23, the launching car 8 is locked in starting position by engagement of a right-angled rocker-arm pawl I8 in a notch I! in the rear lower surface of the brake memher It. The pawl i8 is pivotally mounted between brackets 9! that are secured to the rear structure of the catapult beam l and is locked into initial active position by a toggle link comprising members H and 12 the rounded free-end of member 1i engaging in a curved recess is the adjacent surface of the free end of said pawl l8. When the toggle link is in working position the members H and 72 are at'a position past dead center at their midpoints where they bear against the cam face of a segment 13, Figure 2A,

revolubly mounted upon shaft 13a extending between said brackets 91.

A manual release for the car 8 has been provided and comprises a cable I4, Figures 2A, 21 and 1A, which is led over a sheave 15, within a groove I8 in a portion of the periphery of the cam segment 13, for operatively rota ing the latter to the extent required to operate toggle levers H and 12 to release said pawl it. One endof cable 14 is securedat 14a to segment 13. This system is controlled by a hand lever 11, pivotally mounted at Ila to one side of the support of car 8 and to which lever 71, at a point intermediate its ends, is secured the other end of said cable 14, while the free'end of lever 11 projects beyond the opposite side of car 8 and its support where it maybe normally operated from a position out of the path of travel of said car 8. To supplement the manual control aforesaid, operated by lever 11, a power control is also provided which comprises a cable 18 that passes over the grooved sheave l9 and about a portion of the periphery of grooved sheave 88, to which periphery one end of said cable 18 is secured and said sheave 88 is secured concentric with shaft 131;, to the side of said segment I3. The remaining end of cable I8 is secured, Figures 1A and 2A, to the rigid stem 78a of piston 8| slidable in cylinder. 8| and to which air is admitted at desired times by pipe 82 entering said cylinder 8i upon the side of said piston 18 from which said stem 18a projects. This mechanism is operated by air pressure under control of the master valve H9 supplied through piping 82' to cylinder 8| from a two port valve 83 and a header 84, see Figures 1B and 2B.

To maintain the cables 14 and I8 under tension, and to return piston 18b to its normal position, a wire 85, see Figures 21 and 2A, is connected to the cam segment 13 and to the free end of a leaf spring 88 whose opposite end is securely mounted to and beneath the beam I.

Referring to Figures 2A, 21 and 23, a pin 88 is inserted through a bore extending through the joint 89 hinging the members H and 12 together and said pin 88 also extending through registering apertures in the brackets 91 to prevent accidenial or premature release of car 8 and launching. Unless this pin is withdrawn the airplane cannot be launched even though the valve H9 is operated. The pin 88 is attached to a cable 92 that terminates in a handle 93. A rebound cushion member 94, Figure 21, is secured to said beam I at the limit of the downward movement of link 12 to absorb the shock of the link I2 when it is released.

Referring to Figures 1A, 1B, 1C, 2A, 2B. 2C and particularly to Figures 6 and '7, which show the propelling mechanism, a plunger rod 38 is secured at one end to the movable crosshead 3|.

The plunger rod 38 passes through a packing box that is located upon the forward casting 28 of a cylinder 28 and terminates in a piston 29 within the cylinder 28. The cylinder 28 is held in' position within the structure of the beam l by castings 21 and 28 which are secured to the beam structure I. This cylinder is provided with a series of exhaust ports 38 located near the rear end at a point near theterminus of the power stroke.

These ports 38, when passed by piston 29, permit the greater portion of unspent pressure to be vented to the atmosphere. The rear end of the cylinder 28. between the ports 38 and the rear cylinder head contains air which is decreased in volume and increased in pressure as the piston moves toward the cylinder head, after said piston 29 passes said ports 38. This action brings a force to bear on the piston tending to stop it, the piston rod 38 and the translatable sheaves 82' without depending on the main friction brake to exert the additional force necessary to stop the piston and its attached parts, and without stressing the main cable to transmit the necessary stopping force.

The buifer chamber at the rear end of the piston chamber is provided with a small bent pipe 2. This vent allows a certain portion of the air trapped in the buffer chamber to escape so that as the piston 29 rebounds there is a rarefaction of the air produced in the buffer chamber. This rarefaction of the air within the bufl'er chamber entraps the piston 29 beyond the ports 38 with the result that the jerks upon the driving mechanism which would be produced by the oscillation of the piston 29 back and forth across the ports 98, are eliminated.

In order to govern the speed and to control the acceleration of the airplane during the launching period, a specially arranged control mechanism is provided for controlling the amount of compressed air entering the cylinder 28 from 125 pounds per square inch pressure at the start of car 8 to as much as 500 pounds per square inch, or more, at about the time the craft commences to separate from car 8.

.One of the elements consists of a cam bar 48,

7 Figures '7, 8 and 9, pivotally and adjustably sethe lower end of the shaft'39a, Figures 6, 7 and 8. This shaft carries the sheaves 32 of crosshead 3l. Movement is imparted to the roller 39 as the piston 29 is deliveringits power stroke. A force is exerted upon the cam 48 holding it against the roller 39 by a coil spring 48 Figure 9, which is secured to a 'lever 49 and to the structure of the beam I. .Said lever 49 is pivotally mounted upon the frame structure I' at a point intermediate the ends of said lever 49. The downwardly extending arms 44 of the bell cranks 42 are each pivotally connected to a rod 48 at points 45. This rod '46 is connected to lever 49 by universal joints 41 and pivot 48. The upper end of lever 49 operates a grid valve 53 which controls the amount of compressed air entering the cylinder 26. The lever 49 is pivotally connected to the grid valve 83 through a length adjustable link 58.

The grid valve 53 is housed in an air chamber 52, and constitutes a means forvarying the openings of the ports 54for permitting the desired amount of air to enter the cylinder 28. The air is introduced in substantial volume into the cylinder I 2,127,531 26 through port 54, Figure 9, and thence into the air duct 55, which is located in the casing 28, Fig. 4.

It will be noted that the chamber 52, the lever 49 and its associated linkage have been shown diagrammatically in Figure 9 is order to more clearly illustrate the relation between the grid and the control can 40.

The following details of the grid valve shown inFigure 9 are to be noted: The necessary volume of port opening 54 is obtained by a multiplicity of port openings through valve 53. This is done to limit-the force necessary to-operate the valve to a practical minimum by limiting the air pressure on valve 53 and the distance and velocity of movement of valve 53 necessary to obtain desired results. There is one more grid than port so that the valve 53 may be opened and then closed by a continuous motion of the valve in each direction 53. This also reduces the force, that would otherwise be necessary to transmit through the valve mechanism, by overcoming the necessity of stopping the valve 53 and starting it again in the other direction, and it also allows for an accurate adjustment of the valve 53 even if lost motion is present in the valve system, since it may be set in the original position, with all slack of the valve gear taken up, since the motion during the power stroke is all in one direction. The valve is set so that each port has a lap of for instance three sixteenths of an inch when the catapult is in a condition to start the launching.

storage tank pressure.

The cam 40 is so shaped that the grid valve 53 does not commence to open until. the piston 29 has traveled for instance three inches. Air

necessary to initially start the catapult car 8 flows from the storage tanks 51, 51a, and 5111 through the valve seat 60 of Figure 3 through pipe 66 into the main cylinder 26, thus all of the initial starting air in cylinder 26 by-passes the gridvalve 53 completely. It is to be noted that pipe 66- is small and that the quantity of air flowing through it, during for instance the second and two-fifths required to launch a plane, is negligible compared to the air that later flows through the grid valve 53 and the for instance six inch diameter passage 55, Figure 4 that connects it to the power cylinder 26., As air flows into the main cylinder 26 through the pipe 66 pressure is quickly increased in the cylinder 26 from for instance forty (40) pounds per square inch pressure u ed to take the slack out of the" cable system 25'to the for instance 125' pounds per square inch maximum launching pressure in cylinder 26.. This pressure is transmitted to the header 84. Figure 13, by the pipe 55' and through pipe 82 to the valve 83. The increasing force acting against piston 83 in said valve gradually m ves it to the left against the action of spring 83" and, when the pressure reaches, for instance 125 pounds per square inch the port 82a is uncovered and port 82b is covered. Compressed air rushesthrough said port 82a into pipe 82' and causes the piston 8|, Figure 2A,

in cylinder 8| to move to the right thus releas ing the launching car 8 and allowing it to start down the track under the influence of the force acting through the cable 25.

In such launching movement the crosshea'd 3|,

the disc 6| is seated.

Referring to Figure 5 it will be noted that a- Flgure 8, is moved toward the cylinder 26, carrying the roller 39 Figure 9 with it in contact with the cam surface of the cam bar 40. After traveling for instance three inches the roller 39 begins to move the cam bar 46 thereby bringing the ports and grids of the grid valve edge to edge. The contour of the cam' is so constructed that the quantity of air passing through the grid valve 53 into cylinder 26, taken together with the air flowing through pipe 66 as heretofore described, is just the right quantity to keep the pressure in the cylinder progressively increasing enough to cause the desired launching speed. By keeping the pressure in cylinder 26 sensibly progressively increasing the force acting on the airplane is kept at a gradual progressive increase and therefore at a minimum of shock. This contributes to the comfort of the pilot and to the safety of the whole device. As the piston 29 reaches the ports 38v the cam roller 39 moves the cam 48 at a much more rapid rate in passing over the relatively steep portion of the inclined ,face of cam bar 40,

thus drawing the grids of valve 53 quickly over and closing the ports 54 and thereby preventing air still in the storage tanks 51, 510; and51d, from rushing through valve 53 into cylinder 26 and thence out to the atmosphere through the exhaust ports 38 in the cylinder 26. Air does continue to flow through pipe 66 but by closing the hand wheel 69 of Figure 3 as quickly as practical very little air is wasted. In this manher the air necessary to be pumped into the storage tanks 51 for a second launching is much less than would be necessary if the grid valve 53 was not automatically closed;

Referring particularly to Figures 3, 4 and 5 the grid 53 controls the compressed air entering the cylinder 26 from the valve 56, which is in communication with the storage tank 51.

The valve 56 is joined to the storage system at 59 and is provided with an air passage 58, a valve seat 60, a valve disc 6|, a piston 62 operating in a cylindrical portion 63, pipe 66 for initially admitting air pressure from the passage 58 to cylinder 26, pipe I23 for admitting air pressure from valve 9 to space 10, and a threaded stem- 68, movable independent of valve 6| and piston 62, which is operated by a hand wheel 69 for manually locking both the valve head 6| and piston 62 in a closed position. The valve 56 may be maintained in a closed position either by operation of the hand wheel 69 or by air pressure within the space 16.

The valve 56 consists of a housing that contains two passages 68' and 58. The passage 60' communicates with the storage tank portion 51d. The passage 56 communicates with air space 5| of the chamber 52 in which the grid valve 53 is slidably mounted. Between and separating the passages 58 and 69' is valve seat 60 upon which tank 51 is housed within the catapult beam structure This storage tank, to enable it to be enclosed within and concealed by said beam structure I, is composed of the several members 51d, joined at the ends by elbows 510 connected to opposite ends of tube 51, to constitute a continuous tank or container oneend of which is closed by a header cap 510. The opposite end of the tank is joined to the main valve 56 by a fitting 59 and is used for storage of a gradual accumulation of compressed air from a suitable |4| (Figure 24) but not shown.

with rei'erehce to Figure 24, it will be noted that we have shown the air supply connection M511, through which air" pressure is supplied to the storage tank 51. This connection is located in the central pivot member about which the catapult beam I revolves in being positioned to launch the aircraft in the desired direction.

The connection I851: is located within a central b'ore I88 of a base fitting I85. This fitting is secured to its foundation by bolts. Ia, and terminates in a cylindrical portion I88?) about which a bearing I88 is fitted. The bearing I38 is engaged by a bearing block I31 secured to channel members I38 that are secured to and carried by the structure of the catapult beam I.

The connection I581; consists of a lower nipple M0 which is threaded into a cap I68, and also anupper nipple I84 which is housed and free to rotate within the cap I88. The nipple M0 is connected by a sleeve Mild to the air supply pipe It I and is locked to nipple I in adjusted position by a threaded collar I42, and sealed against leakage of air by packing gaskets M8 between said collar I42 and the adjacent face of the sleeve of cap I48. The nipple I is sealed against leakage of air by gaskets I85 and 8a. A squared upper portion is provided in the stem of the nipple at I840 for engagement of locking plates I48 as shown. in Figures 24, 25. The plates I58 are secured to a cross member It? by means of bolts. The'cross' member MI is secured to the structural members I88 of beam I by bolts at opposite ends. Said plates I88 compel nipple I86. to rotate in unison nigh the catapult beam construction I, I88 and A braking system shown more clearly in Figures 10, 2C and 22 is located toward the front of the catapult beam structure I. Its function is to pro.- gressively bring the launching car 8 to a stop at the end of the accelerated run. The brake friction member it carried by the car 8, at each complete cycle oi movement of car 8, passes between a pair of brake shoes 88' and on opposite sides of a central rail portion 9? of a casting 88 rigidly secured to and which projects above the structure I, and said rail 91 extends throughout thewhole space in which the deceleration of car 8 is effected. The brake shoes 88 are pivotally connected at one end of 81a, and rest in bearings 8841, Figure 10, of the casting 88. Adjacent their pivot points 81a the brake-slices 88 are. provided with a beveled throat 81c, shown in Figure 10, which, with said pivotingof shoes 88, relieves the shock of brake friction members I8 entering between said shoes 88.

The end of said central rail 91 toward car 8 in its initial or locked position, is provided with a taper, as 81b of Figure 16 to insure the friction members I4 straddling said rail 8'! without shock.

The brake system has a series of brake operating units I80, in opposed pairs. Each unit shown in detail in Figure 22 consists of a pair of levers IOI These levers are mounted on pivots I82 that rest in bearings I88, rigid on frame member I, one on each side of the casting 88.

' The lowerends of the levers are connected by toggle links I88, links I I2 and a spring I I8. Links II! at the ends oi the levers are provided with elongated bearingsto limit the movement, and springs 8 hold the members against vibration and out of braking engagement. Connected to the toggle link II! at the middle pivot I88 is a connecting rod III which terminates in a piston III that is siidabie in a cylinder I88. This cylinder is mounted upon the lower side of casting 98.

The springs, H3 normally hold shoes 88 out of braking contact with the braking friction members III which are connected together along their upper edges bya U-shaped member Ida, Figure 22,

relatively thinner than said members It, and, when said members I' l are under the braking pressure of said shoes 96 said members are thereby also held-in braking engagement with the lateral surfaces of the center rail 91 while said last named engagement is released by the spring of the metal inherent in said U-shaped portion Ma of member I4 upon release of'shoes 96.

For the application and regulation of the braking pressure compressed air is supplied to chamber between the piston I07 and the cylinder I88 by means of a pipe I08.

The pipe I09 is connected to pairs of cylinders as shown in Figure 2C. Pipe I08 also connects through pipe III, safety blow-oil valve H6, and regulator valve H5 to pipe I It, as shown in Figu'res 1B and 2B. The pressure in the cylinders I08 is registered on gage I I8 which is connected to the fathermost end of pipe I I1.

Referring to Figures 113, 2B and 10, it is to be noted that the master control valve H8 operates the various units in theifirespective order of sequence, and is conveniently located upon the seat l2 la is a movable head I21 that carries upon its upper surface a bearing seat IZ'Ia. The movable head I2'I is operated by a handle F extending therefrom. Extending through the yoke extending from the body I H is a screw I28, the tapered lower extremity of which rests in bearing seat I2Ia, Figure 10, the relative neutral axis of said seat l2 Ia head I21 and screw I26 being coincident. By adjustment of the screw I28 an air-tight connection between the movable head I21 and the valve seat I2Ia. is accomplished and maintained. When the proper adjustment is reache at each adjustment the screw I26 is locked in pa ition by means of a. lock nut I28a.

Within the valve seat I2Ia are a plurality of passages L and M surrounding but separated from the concentric inlet passage "11 by partitions I2Ic.

Within the movable head I27 are a plurality of passages E, G, :i and H. The passage H in head I2'I coincides at all times with the passage H in the valve seat Illa. V

The valve 9 has four operative positions, the first of which is shown in Figures 10, 13 and 14. The'second position is approximately 40 degrees of rotation in a clockwise direction of the movable head I2'I, as shown in Figures 15 and 16. The'third position is approximately I5 degrees of rotation in a clockwise direction from the initial position, as shown in Figures 17 and 18.

The fourth position is approximately 150 degrees Figure 12 is a sectional view of the movable head I21 on the line II--II of Figure showing the elongated ports E and G in the base of the mov- 84 (Figure 23), pipe I22, Figures 23 and 10, passage L in the 'valve seat and passage E in the movable valve head I21, Figure 14. The passage M, which communicates with pipe I23 which in turn communicates with valve 56, Figure 3, and

gauges 65, is closed as shown in Figure 14.

The passage H connects with the source of compressed air and the storage tank. 51 through pipes I3I and H4. This position maintains the entire mechanism in' readiness for a launching.

lows:

A blow-off valve I28 (Figures 13 and 2B) in piping I I4 is first opened so that any moisture or foreign matter may be blown out of the air supply line I I4. Then the valve I28 is closed and valves I29 and I30 are opened and which normal ly double seal the high pressure'air supply coming from stationary piping MI and movable piping II-4. This opening of valves I29 and I38 permits air pressure to accumulate in the storage tank 51 by the flow ofair through said valves to piping I3I until the proper amount of air pressure is reached in tank 51, as indicated on a gauge I 32. This gauge is in communication with the storage tank. 51 through piping I33. A safety valve I34 is provided in head 51C of said tank 51 to protect the accumulator system, comprising storage tank 51 and its associated piping,

from receiving any substantial excess of maximum pressure.

The handle F of the valve H9 is moved from the closed position shown in Figure 13 to a position shown in Figures and 16. In this position.

the cylinder 26 is vented to the atmosphere in" the manner similar to that shown in Figures 10, 13 and 14. The passage H, however, now communicates with the passage M, through passage G. This position allows air to pass from the storage tank 51 through pipes I3I and H, passages H, G and M through piping I23, to the the valve stem 68 by operation of the hand wheel 69.

Valve H5 in piping III, communicating with the main air supply piping I I4, being closed, blowofi valve H6 is opened to release any air pressure there may be in piping I I I, I89 and cylinder I88, which releases the backing pressure of shoes 98 and central rail 91 upon opposite sides of the brace friction members, I4and enables the car 8, movable cross-head 3|, and piston 29 to be manually returned to normal position and said car 8 locked by detent I6 engaging in notches I5 in the rear lower surface of brake friction members I4 secured to the bottom of car 8; said manual return of said parts being by pushing car 8 back to normal position. However, in practice, when valve II5 is shut off at the conclusion of a launching the airleakage from cylinders I88 around pistons I81 is such that before further launching is required there is no pressure on pisbraking system (see Figures 10 and 22).

The further operation of the device is asfoltons'lli1, and springs H3 have released car 8 from the braking action of shoes 96 and 91. The manual releaseof detent I6 by lever 11 maybe accomplished when air pressure is absent from cylinder 26 to enable car 8 to be manually moved for any temporary purpose other than launching aircraft. I

The valve H5 in the piping III is then opened to admit air pressure to the pistons I81 of the This pressure is indicated by the gauge II8 connected by piping I I1.

The safety pin 88 is then removed (see Figures 2A, 21 and 23) preliminary to the actual launch- The master valve 119 (Figure 10) is advanced to the third position shown in Figure 1'1, and is used as a throttle to maintain .an air pressure of about 40 pounds per square inch in the main cy1-. inder 26. In this position air flows from the tank through piping I 3I, passages H, J and L of the master valve, (Figure 1'7), piping I22, header tank 84, pipe 55 to space 55 which communicates with the main cylinder 26. This pressure in the main cylinder is indicated by gauge 65.

These last'named operations bring all parts of the towing mechanism under tension, and overcome any jerking at the start that would occur if any slack existed.

The master valve is then advanced to the fourth position shown in Figures 19 and 20. The passage L is now blanked off. No air flows through the master valve either into or from the main cylinde'nbut flows from chamber 10 (Figure 3) of the main valve 56 through pipingl23 and through passages M and E, Figures 19 and 20, to the atmosphere, thus relieving the pressure previously built up in the chamber 16. As soon as the force exerted on the piston 62 of the main valve 56 falls below that exerted on the valve 6| by the pressure withinthe storage tank 51 the valve 6I will open and the air contained in the storage tank 51 flows through piping 66 into the header tank 84 (Figure 1B) and through piping 55' into the main cylinder. The pressure in the main cylinder 26 will begin to build up to a value somewhat lower than the pressure within the storage tank 51.

Whatever pressure is present in the header tank 84 at any time will 'be communicated through piping 82 to valve 83 (Figure 1B) and will act against piston 83 and spring 83". This piston and spring are so designed that a pressure of 125 pounds per square inch is required to force the piston back far enough to open the port 82a, and close the port 82b. Until the piston is acted upon by suflicient pressure to uncover port 82a, any air that leaks past the piston into port 82a is vented by port 8217, through the valve casing to the atmosphere. 7 This avoids the possibility of building up pressure in the pipe 82 which might otherwise cause the release mechanism actuated by piston 8| to function too soon. When the pressure in the main cylinder 26 and header tank 84 reaches the required pre'ssure, the piston'83 uncovers port 82a and covers 82b, so air flows through piping 82 into the cylinder 8I, Figures 1A. and 2A. This'pressure actuates a piston 8I' inside the cylinder 8I, Figures 1A and 2A, which motion releases the locking mechanism on the car as described with reference to Figures 2A and 21.

The air flowing from the storage tank 51 (Figure 5) into the main cylinder 26 through piping 66 (Figure 3) the header 84 (Figure 1B) and the piping 55' (Figure 7), builds up suflicient pressure to cause the piston 29 to operate through the translatable sheaves 32 and 35, and cable 25 to take up the slack in the mechanisms between the car 8 and the piston 29. The removal of this slack prevents any sudden jar upon the car when the car 8 is released by the main air pressure introduced into the cylinder 26. Immediately after this operation the grid valve 53 opens and permits the direct flow of a large quantity of air from the storage tank 51 through the valve 60, the passage 58 and through the grids of the valve 53, directly into the piston chamber. This flow of air by means of the cam bar 40 control 'of the grid valve 53 develops a substantially constantly accelerated pressure throughout the power stroke, thus driving the plane at a uniform acceleration to the end of the power stroke; when the air supply is cut off by the grid valve 53; and the air in the cylinder commences to escape through the ports-38, just before the car enters the brake shoes 96. The purpose is to release the plane from the car when no force is acting between them, which occurs when the velocity of the plane being launched exceeds the velocity of car 8 due to the combined influence thereonof car 8 and of its propeller action.

When the car approaches the end of the track the brake friction-members I4 engage shoes 96 of the braking system. By this engagement the car 8 is gradually brought to a stop by a uniform deceleration which may be safely accomplished at the rate of as much as times the acceleration. of gravity, requisite for the extremely limited space alfordable therefor, as the airplane is released from said car 8 and continues under the force of its thus imparted initial acceleration and under its own power. If valve 6| be omitted and grid valve 53 alone controlled the flow of air to cylinder 26, car 8 could not be manually'returned to its initial position since the sharp incline on the lower surface of the cam bar 40, near its left end, in Figure 9, by the cooperation therewith of roller 39, closes grid valve 53 while the parallel lower surface of said cam bar 40 to the left of Said sharp incline retains said valve 53 in its closed position, and since said return of car 8 causes said roller 39 to travel from its dotted position shown in Figure 9 toward the right, said roller in starting down said sharp incline on said bar 40, causes said valve 53 to open and the pressure in tank 51, 51d will cause said car 8 to be again exerted on piston 29 to move said car forward from. said point. Therefore, before car Bean be manually returned said valve 6| must be held to its seat either by air pressure in chamber 10 or by the independent threaded stem 68, of valve 6|, operated' by wheel 69.

The requisite short period of the launching time which is from about three quarters of a second to one and a-half seconds, is too short to permit the manual opening of valve 6| by wheel 69 or otherwise, and to overcome this difliculty we have devised the means of making said stem 68 separate from valve 6| and adapted to contact with said valve 6| to seal it shut as well as to limit the degree said valve 6| may be opened by the force of the air it is adapted to keep from valve 53.

The air pressure from the common source, supplied through waster valve 9 by pipe I23 to chamber 10, and against piston 62, holds valve 6| firmly to its seat, when present and when stem '68 is removed from contact with said valve 6|. Such ail; pressure in chamber I6 may be instantly released and valve 6| correspondingly opened to the degree permitted by the extent that said stem 68 is manually withdrawn from contact with a portion of valve 6|, and which degree controls the velocity of car 8 in its launching movement so that said velocity may be thus controlled both within the time above specified as well as for any increase that may be desired in said specified time.

It is essential that car 8 be latched at a fixed immovable point as if said point be movable or yielding the travel space of car 8 into its launching movement is detracted from to said extent which results in a less than normal launching velocity.

The fact that in all practical launching means the pressure upon the lock locking the launching car in its initial position is from eight thousand to twelve thousand pounds, for instance, upon the relatively small area of said lock in contact with said car, at the time of the release of said lock precludes any direct manual releasing of such locks of the prior art. the toggle levers II, 12 and their cooperating cam I3 provide an emcient means of lockingand unlocking said lock subjected to such pressure and that such means may be actuated normally as well as by power, and further that it is essential to the aircraft personnel, as well as to the plane that accelerations of the launching movement be gradual and not sudden.

The pivoting of lock member I6 at a point I6a.

means for permitting said member I6 being tilted forward and downward, affords a definitely controlled gradual starting of car 8 such as will not distress either said personnel or plane, Besides said toggle levers II, 12 being then in substantially a straight line and in contact with said cam 13 only at the intermediate joint of said toggle occasions but little of the force on said cam that is exerted by said car 8 upon pivoted lever I6, practically all of said force being borne by the stationary fulcrum of said toggle and thus it requires but little force of said cam I3 to move said toggle members II, 12 beyond a. straight linefrom which point the stress of car 8 on lock rockerarm I6 completes the unlocking of said car. The opening Ha, through the side member I of the framework supporting the tracks I8, and in line with the point of contact of toggle lever II with rockerarm lock 'lfi, enables the convenient-insertion of pin 88 and a ready View by an operative to determine that said members are in operative relation before even the pressure is applied to piston 26 to take the slack out of the mechanism precedent to applying the supplemental lock releasing and the launching pressures.

The arrangement of the gauges I I8, 65, 84' and I32 adjacent the master valve 9, see Figures 13 and 23, has been devised to afford the operator of said valve to determine at a glance that the several coordinated means, in communication with their respective said gauges, are functioning properly.

While the proximity of valves H5, I30 and the manual control wheel 69 of valve 6| to said master valve 9 has been devised to enable the operator 'of said valve M9 to readily operate each of said stated other valves, when required with little if any movement from his usual operating position.

The pipe MI, Figure 24, leading from the source of air pressure supply, entering the launching mechanism through the tubular cen- We have discovered that a below its cooperating notch I5 together with the ter of the swivel mounting of the launching 75 mechanism has been devised-to relieve said swiv- .el-mounted launching mechanism of the strain -the more readily relatively moved, with less friction and wear, in the launching of the planein the most advantageous direction.

The swivel mounting of the launching mechanism upon a relatively long stationary bearing member (l35b, Fig. 24) extending between the relatively wide channel bars I38 of the launching means framework, and having a bearing surface extending substantially the width of said bars I38 and whose cooperating bearing sleeve (I31) is revoluble thereon and secured to and between said bars at a point adjacent said hearing member has been devised by us for the further purpose of affording lightness, strength, compactness and disposing the main hearing so as to resist the great longitudinal stress on the launching framework occasioned by the launch-' ing and deceleration of car 8.

The nesting of the auxiliary air pressure tank members 51, 51a, 51d has been devised to carry, in compact form between and protected'by, the closely spaced channel bars I38, Figure 24,01? the launching framework, the supply of air pressure, in excess of the volume thereof required for any launching, andclose to the means upon which suchpressure is to be exerted.

The provision of the main valve means 56, Figures 3 and 5, secured directly to one end, and of substantially the diameter of auxiliary air pressure supplytank 51, with the securement of the car travel control valve 52 to the otherv end of said relatively short valve means 56 and the connection of said valve 52 into the end of cylinder 26, to admit the air pressure through ample'short connections in the direction of working travel of piston 29, has been devised to facilitate the obtainance of the requisite launching velocity in the extremely short time and travel space affordable upon'a vessel without substantial impairment of the normal other functions of such vessel.

The leakage of air around each of the pistons I61 in cylinders I68 has been "devised for the purpose of avoiding undue or dangerous pressure in said cylinders and their piping I II and I" repermits piston 83' to close pipe 82 from the atmosphere and permit said pressure to enter pipe 52' and proceed thence to piston 8| and operate cable 18 -torelease lock l6 of car 8; but before said car release is accomplished the air pressure against piston 29 and 83' has been increased from the initial slack removing pressure, of for instance 40 pounds per square inch, to said higher pressure, for instance of 120 pounds per square inch, by pipe 55' from header 84, Figure 13, into connection, Figure 4, opening into cylinder 26, as well as above said higherpressure to the extent of the initial applicationto piston 29' of the launching pressure, but not the maximum of said pressure as far as we have been able to use practically with safety to pilot and the mechanism, before car 8 is unlocked and permitted to commence its launching movement. While this places very substantial stress upon the relatively small surface of-detent I6, in contact with notch IS in car 8, yet such progressively applied pressures are essential upon piston 29 in order to practically accomplish the plane launching in the extremely limited space available, for instance upon a ship, with safety to the pilot and mechanism. Such progressive increment of said pressures before, as well as after, the unlocking of car 8 contributes .substantially to the smoothness of operation of the mechanism without shock or counteracting for plane launching in the extremely limited space available.

The pressure supply means I supplies air pressure, from a power plant located independent of the swiveled upper portion of the launching means, to the storage tank within saidlatter means ;.and this was devised to enable said storage tank to act as 'an accumulator from a relatively small power plant, as if the 'air pressure were directly supplied from a power plant to cyllength may be afforded by the plane itself or by independent power which does not ordinarily ,involve difficult problems; but the safe and successful launching of a plane by independent power required to be exerted, accelerated and decelerated in a relatively limited space, especially in such an extremely limited space as afforded on a ship, for-instance, involves intricate problems of great dimculty whose successful solutionrequires and includes the selection of the agencies and means the precise coordination thereof, great refinement of detail, the ascertainment and utilization of the most eflicient relative weights, acceleration and deceleration velocities of 'the parts and the stresses thereon, the utilisation of every means even of minor separatetendencies, and their coordinated mass effect upon each of the functions as well as upon the ultimate result.

The presence or absence of many, if not all of these in such a method and structure operable in such a limited space contribute to the success or failure of the objective.

It will be understood that the above description and accompanying drawings comprehend only the general and preferred practice of our method as well as mechanical embodiment of our invention and that minor detail changes in the method, construction and arrangement of parts may be made .within the scope of the appended claims without sacrificing any of the advantages of our invention.

The invention herein described maybe manufactured and used by or for the Government of the United States for governmental purposes without the payment to us of any royalty thereon or therefon. i

What we claim is as follows:

1. In an airplane launching catapult. having. a

15 vibrations at the necessary high velocity requisite track and a launching car thereon, the combination of a fluid storage tank, means for introducing afluid within the tank under pressure, means for transforming the energy contained in the compressed fluid into movement of the car along the track, means for securing said car in initial position on said track, and means independent of said securing means for releasing said securing means by an independent application of said fluid.

2. In an airplane launching catapult, having a track and a launching car thereon, the combination of a fluid storage tank means for introducing a fluid under pressure within the tank, a cylinder, a piston within the cylinder, means for transferring the fluid from the tank to within the cylinder, means for transmitting the motion of the piston to the car for translation of the car along the track, means for securing said car in initial position on said track, and means independent of said securing means for releasing said securing means by an independent application of said fluid.

3. In an airplane launching catapult, having a track and a launching car thereon, the combination of a-fluid storage tank, means for introducing a fluid within the tank under pressure, a cylinder, a piston within the cylinder, means for imparting movement of the piston to the car, means for transferring fluid from the storage tank to the cylinder for initially moving said car, and means including a cam for automatically admitting, regulating and closing the further flow of fluid from the storage tank into the cylinder as the car progresses along the track.

4. In an airplane launching catapult, having a track and a launching car thereon, the combination of a fluid storage tank means for introducing a fluid within the tank under pressure, a cylinder, a piston within the cylinder. motion multiplying pulleys and cables connecting the car and the piston, a braking mechanism located near the end of the catapult track, means for transferring the compressed fluid from the storage tank to the cylinder, means upon the car for engaging the braking mechanism as the car approaches the end of the track, and means including a cam for progressively admitting, controlling and discontinuing the pressure within the cylinder as the car moves along the track.

5. In combination with an airplane launching catapult having a track, a car movable along the track and means for driving the car along the track, means for locking the car in starting position, means for releasing said locking means;

. means for applying power to said first named means while said locking means holds said car, and means for substantially simultaneously applying further power to said first named means and independently applying said further power to said means for releasing said locking means.

6. In combination with an. airplane launching catapult having a track, a car movable along the track, means for driving the car along the track, means for locking the car in starting position and means for automatically unlocking the car and actuated by theindependent application of an independent part of the force which actuates said first named means.

7. In combination with an airplane launching catapult having a track, a car movable along the track, means for driving the car along the track, means for locking the car in starting position, means for automatically unlocking the car and actuated by the independent application thereto of an independent part of the force which actuates said first named means, means for securing, against vertical and other substantial relative movement, said plane and car at a plurality of separated points in the direction of said track, and means for releasing theairplane from the car.

8. In combination with an airplane launching catapult having a track and a car upon the track, means for locking the airplane to the car at a plurality of points separated in the direction of said track, and means for automatically releasing the airplane from said car successively at said points, said successive release commencing after the car and airplane have travelled a predetermined distance along the track.

9. In combination with an airplane of launching means therefor, bolt and bolt-keeper means for locking from substantial movement in all directions said airplane to an element of said means at a plurality of points separated in the direction in which said plane is launched, and

-means for successively releasing said locking means.

10. In combination with an airplane of launching means therefor, separate coating bolt and bolt-keeper means carried by the airplane and an element of said means at a plurality of points separated in the direction in which the plane is launched for locking said airplane to an element of said means at each of a plurality of points separated in the direction in which said plane is launched, and means for successively releasing said locking means.

11. In combination with a normal airplane, of launching means therefor, separate means for locking said airplane to an element of said means at each of a plurality of points on opposite sides of said plane, said points being separated in the direction in which said plane is launched, and means for successively releasing said locking means.

121 In combination with an airplane of launching means therefor, means for locking said airplane to an element of said means at a plurality of points separated in the direction in which said plane is launched, and means for successively releasing said locking means at intervals in the launching movement of said plane and commencing with the rearmost locking means.

13. In combination with an airplane of launching means therefor having a car adapted to sup- I port said plane; and means, including a pin and coacting keepers therefor on said car and plane with said pin extending in the launching direction, for removably securing said plane to said car.

14. In combination with an airplane of launching means therefor having a car adapted to support said plane; and means, including a plurality of pins extending substantially in the launching direction and each provided with coacting keepers therefor, for removably securing said plane to said car.

15. In combination with an airplane launching catapult having a track, and a car upon the track, means for locking the airplane to the car said means consisting of a plurality of keeper plates mounted upon the car, pins mounted within the keeper plates, a plurality of wires fastened to the airplane and held by the pins, and means for removing the pins after a predetermined distance of travel of the car along the track.

16. In combination with an airplane launching catapult having a track, and a car upon the track,

means for locking the airplane to the car said means consisting of a plurality of keeper plates mounted upon the car, pins mounted within the keeper plates, a plurality of wires fastened to the airplane and held by the pins and means for removing the pins after a predetermined distance of travel of the car along the track, said means consisting of a plurality of slack cables one end of each cable fastened to the track and the other end engaging the pin in each of the keeper plates.

17. In combination with an airplane launching catapult having a track and a car upon the track,

means for locking the airplane to the car, means for releasing the airplane from the .car and means acting at a substantial angle to the direction of movement of said car for producing a gradual retardation of the'movement of the car. along the track as the car approaches the end of the launching run.

18. In combination with an airplane launching catapult ha ing a track and a car upon the track, means for locking the airplane to the car, means for releasing the airplane from the car after a predetermined distance of travel of the car alon the track; and a plurality of pneumatic means,

each progressively commencing to act upon said carfor producing a gradual retardation of themovement of the car along the track as the car approaches the end of the launching run.

19. In combination with an airplane launching catapult having a track and a car upon the track, means for locking the airplane to the car, means for releasing the airplane from the car after a predetermined distance of travel of the car along the track, and pneumatic means for producing a gradual retardation of the movement of the car along the track as the car approaches the end of the launching run, said means consisting of a brake member rigidly attached to the lower side of the car, a plurality of brake shoes movably mounted upon the track and adapted to engage said brake members, a plurality of levers one end of which engage the brake shoes, the other end of which are connected together by a toggle joint, a piston connected to the mid-point of the toggle joint, a cylinder surrounding the piston and means for forcing a fluid under pressure into the space between the cylinder and the piston.

20. In combination with airplane launching means and a support therefor, of a brake shoe secured to a movable element of said means, a pair of brake-shoes mounted on said support opposite each other and on opposite sides of said brake shoe mounted on said support for actuating said shoes to produce braking stress on opposite sides of said pair of first named braking shoe.

21. In combination with airplane launching means and a support therefor, of a brake shoe secured to a moving element of said means, a

plurality of pairs of brake shoes mounted opposite each other and on opposite sides of said brake shoe, in the path of the latter portion of travel of said element, means for movably mounting said pairs of shoes on the support for said launching means mounted on said support for simultaneously actuating said pairs of shoes to produce braking stress on opposite sides of said first named braking shoe in the latter portion of its travel.

22. In combination with airplane launching means and a support therefor, of a brake member secured to a moving element of said means, brake shoes mounted opposite each other and on opposite sides of said brake member, in the path of the latter portlon of travel of said element, means for movably mounting said shoes on the support for said launching means, supplemental shoes on the sides of said brake-shoes, and means for actuating said shoes to produce braking stress on opposite sides of said braking member in the latter portion of its travel.

23. In combination with airplane launching means having a support, of a brake shoe secured to a moving element of said means, additional brake shoes mounted opposite each other and on opposite sides of said brake shoe, in the path of the latter portion of travel of said element, means for movably mounting said additional shoes on the support for said launching means, and a plurality of means mounted on said support and disposed in the direction of the extent of said shoes for simultaneously actuating said additional shoes to produce braking stress on opposite sides of'said braking shoe.

ment, means for movably mounting said shoes on the support for said launching means, the ends of said shoes approached by said brake member being provided with a beveled mouth, and means for actuating said shoes to produce braking stress on opposite sides of said braking member in the latter portion of its travel.

25. In an airplane launching mechanism, a base, launching means, means for swiveling said launching means to said base and having" an opening through its neutral axis, means independent of said launching means for supplying power, means for storing said power, means for mounting said storing means on saidswiveled launching means, means extending .into said opening and flexibly connecting said power sup- ,ply and said power storage means, and means for transforming said stored power into launching movement of said airplane.

26. In an airplane launching mechanism, a base, launching means, means for swiveling said launching means to said base and having an opening through its neutral axis, meansfor storing a power medium, means for mounting said storing means on said swiveled launching means, means for passing a power medium into and out of said openingand to said storing means, and means for transforming said stored power medium into launching movement of said airplane.

27. In an airplane launching mechanism, a car,

means for removably securing said plane upon said car, means for securing said car from move- 'ment, means for generating a pressure to be applied to said car, means for applying some'of said pressure to said secured car, means for successively applying further pressure to said car and releasing by said further pressure said means for securing said car, means for accelerating said pressure upon said car, means for decelerating said car in the latter portion of its travel, and means for releasing said plane from said car.

28. In an airplane launching mechanism, a car, means for removably securing said'plane upon said car, means for securing said car from movement, means for generating a pressure to be applied to said car, means for applying some of said pressure to said secured car, and means for successively applying further pressure to said car 

